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[Qemu-block] [PATCH v2] migration: disallow migrate_add_blocker during m
From: |
John Snow |
Subject: |
[Qemu-block] [PATCH v2] migration: disallow migrate_add_blocker during migration |
Date: |
Wed, 30 Sep 2015 13:07:29 -0400 |
If a migration is already in progress and somebody attempts
to add a migration blocker, this should rightly fail.
Add an errp parameter and a retcode return value to migrate_add_blocker.
This is part one of two for a solution to prohibit e.g. block jobs
from running concurrently with migration.
Signed-off-by: John Snow <address@hidden>
---
block/qcow.c | 6 +++++-
block/vdi.c | 6 +++++-
block/vhdx.c | 6 +++++-
block/vmdk.c | 7 ++++++-
block/vpc.c | 10 +++++++---
block/vvfat.c | 20 ++++++++++++--------
hw/9pfs/virtio-9p.c | 16 ++++++++++++----
hw/misc/ivshmem.c | 5 ++++-
hw/scsi/vhost-scsi.c | 25 +++++++++++++++++++------
hw/virtio/vhost.c | 35 +++++++++++++++++++++++------------
include/migration/migration.h | 6 +++++-
migration/migration.c | 32 ++++++++++++++++++++++++++++----
stubs/migr-blocker.c | 3 ++-
target-i386/kvm.c | 16 +++++++++++++---
14 files changed, 146 insertions(+), 47 deletions(-)
diff --git a/block/qcow.c b/block/qcow.c
index 6e35db1..fbb498f 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -236,7 +236,11 @@ static int qcow_open(BlockDriverState *bs, QDict *options,
int flags,
error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail;
+ }
qemu_co_mutex_init(&s->lock);
return 0;
diff --git a/block/vdi.c b/block/vdi.c
index 062a654..1635ab1 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -505,7 +505,11 @@ static int vdi_open(BlockDriverState *bs, QDict *options,
int flags,
error_setg(&s->migration_blocker, "The vdi format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail_free_bmap;
+ }
qemu_co_mutex_init(&s->write_lock);
diff --git a/block/vhdx.c b/block/vhdx.c
index d3bb1bd..097c707 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1005,7 +1005,11 @@ static int vhdx_open(BlockDriverState *bs, QDict
*options, int flags,
error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail;
+ }
return 0;
fail:
diff --git a/block/vmdk.c b/block/vmdk.c
index be0d640..36ff6f4 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -951,7 +951,12 @@ static int vmdk_open(BlockDriverState *bs, QDict *options,
int flags,
error_setg(&s->migration_blocker, "The vmdk format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail;
+ }
+
g_free(buf);
return 0;
diff --git a/block/vpc.c b/block/vpc.c
index 2b3b518..f3dd677 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -325,13 +325,17 @@ static int vpc_open(BlockDriverState *bs, QDict *options,
int flags,
#endif
}
- qemu_co_mutex_init(&s->lock);
-
/* Disable migration when VHD images are used */
error_setg(&s->migration_blocker, "The vpc format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail;
+ }
+
+ qemu_co_mutex_init(&s->lock);
return 0;
diff --git a/block/vvfat.c b/block/vvfat.c
index 7ddc962..bdc1297 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1191,22 +1191,26 @@ static int vvfat_open(BlockDriverState *bs, QDict
*options, int flags,
s->sector_count = s->faked_sectors +
s->sectors_per_cluster*s->cluster_count;
- if (s->first_sectors_number == 0x40) {
- init_mbr(s, cyls, heads, secs);
- }
-
- // assert(is_consistent(s));
- qemu_co_mutex_init(&s->lock);
-
/* Disable migration when vvfat is used rw */
if (s->qcow) {
error_setg(&s->migration_blocker,
"The vvfat (rw) format used by node '%s' "
"does not support live migration",
bdrv_get_device_or_node_name(bs));
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail;
+ }
}
+ if (s->first_sectors_number == 0x40) {
+ init_mbr(s, cyls, heads, secs);
+ }
+
+ // assert(is_consistent(s));
+ qemu_co_mutex_init(&s->lock);
+
ret = 0;
fail:
qemu_opts_del(opts);
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index f972731..67dc626 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -978,20 +978,28 @@ static void v9fs_attach(void *opaque)
clunk_fid(s, fid);
goto out;
}
- err += offset;
- trace_v9fs_attach_return(pdu->tag, pdu->id,
- qid.type, qid.version, qid.path);
+
/*
* disable migration if we haven't done already.
* attach could get called multiple times for the same export.
*/
if (!s->migration_blocker) {
+ int ret;
s->root_fid = fid;
error_setg(&s->migration_blocker,
"Migration is disabled when VirtFS export path '%s' is
mounted in the guest using mount_tag '%s'",
s->ctx.fs_root ? s->ctx.fs_root : "NULL", s->tag);
- migrate_add_blocker(s->migration_blocker);
+ ret = migrate_add_blocker(s->migration_blocker, NULL);
+ if (ret < 0) {
+ err = ret;
+ clunk_fid(s, fid);
+ goto out;
+ }
}
+
+ err += offset;
+ trace_v9fs_attach_return(pdu->tag, pdu->id,
+ qid.type, qid.version, qid.path);
out:
put_fid(pdu, fidp);
out_nofid:
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index cc76989..859e844 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -740,7 +740,10 @@ static int pci_ivshmem_init(PCIDevice *dev)
if (s->role_val == IVSHMEM_PEER) {
error_setg(&s->migration_blocker,
"Migration is disabled when using feature 'peer mode' in
device 'ivshmem'");
- migrate_add_blocker(s->migration_blocker);
+ if (migrate_add_blocker(s->migration_blocker, NULL) < 0) {
+ error_report("Unable to prohibit migration during ivshmem init");
+ exit(1);
+ }
}
pci_conf = dev->config;
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index fb7983d..46ab197 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -239,8 +239,14 @@ static void vhost_scsi_realize(DeviceState *dev, Error
**errp)
vhost_dummy_handle_output);
if (err != NULL) {
error_propagate(errp, err);
- close(vhostfd);
- return;
+ goto close_fd;
+ }
+
+ error_setg(&s->migration_blocker,
+ "vhost-scsi does not support migration");
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ goto free_blocker;
}
s->dev.nvqs = VHOST_SCSI_VQ_NUM_FIXED + vs->conf.num_queues;
@@ -253,7 +259,7 @@ static void vhost_scsi_realize(DeviceState *dev, Error
**errp)
if (ret < 0) {
error_setg(errp, "vhost-scsi: vhost initialization failed: %s",
strerror(-ret));
- return;
+ goto free_vqs;
}
/* At present, channel and lun both are 0 for bootable vhost-scsi disk */
@@ -262,9 +268,16 @@ static void vhost_scsi_realize(DeviceState *dev, Error
**errp)
/* Note: we can also get the minimum tpgt from kernel */
s->target = vs->conf.boot_tpgt;
- error_setg(&s->migration_blocker,
- "vhost-scsi does not support migration");
- migrate_add_blocker(s->migration_blocker);
+ return;
+
+ free_vqs:
+ migrate_del_blocker(s->migration_blocker);
+ g_free(s->dev.vqs);
+ free_blocker:
+ error_free(s->migration_blocker);
+ close_fd:
+ close(vhostfd);
+ return;
}
static void vhost_scsi_unrealize(DeviceState *dev, Error **errp)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index c0ed5b2..0de7a01 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -926,13 +926,25 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
goto fail;
}
- for (i = 0; i < hdev->nvqs; ++i) {
- r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i);
- if (r < 0) {
- goto fail_vq;
- }
- }
hdev->features = features;
+ hdev->migration_blocker = NULL;
+
+ if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
+ error_setg(&hdev->migration_blocker,
+ "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature.");
+ r = migrate_add_blocker(hdev->migration_blocker, NULL);
+ if (r < 0) {
+ errno = -r;
+ goto fail_mig;
+ }
+ }
+
+ for (i = 0; i < hdev->nvqs; ++i) {
+ r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i);
+ if (r < 0) {
+ goto fail_vq;
+ }
+ }
hdev->memory_listener = (MemoryListener) {
.begin = vhost_begin,
@@ -949,12 +961,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
.eventfd_del = vhost_eventfd_del,
.priority = 10
};
- hdev->migration_blocker = NULL;
- if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
- error_setg(&hdev->migration_blocker,
- "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature.");
- migrate_add_blocker(hdev->migration_blocker);
- }
+
hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions));
hdev->n_mem_sections = 0;
hdev->mem_sections = NULL;
@@ -965,10 +972,14 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
hdev->memory_changed = false;
memory_listener_register(&hdev->memory_listener, &address_space_memory);
return 0;
+
fail_vq:
while (--i >= 0) {
vhost_virtqueue_cleanup(hdev->vqs + i);
}
+ migrate_del_blocker(hdev->migration_blocker);
+fail_mig:
+ error_free(hdev->migration_blocker);
fail:
r = -errno;
hdev->vhost_ops->vhost_backend_cleanup(hdev);
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 8334621..fc18956 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -117,6 +117,7 @@ int migrate_fd_close(MigrationState *s);
void add_migration_state_change_notifier(Notifier *notify);
void remove_migration_state_change_notifier(Notifier *notify);
bool migration_in_setup(MigrationState *);
+bool migration_has_started(MigrationState *s);
bool migration_has_finished(MigrationState *);
bool migration_has_failed(MigrationState *);
MigrationState *migrate_get_current(void);
@@ -150,8 +151,11 @@ void ram_handle_compressed(void *host, uint8_t ch,
uint64_t size);
* @migrate_add_blocker - prevent migration from proceeding
*
* @reason - an error to be returned whenever migration is attempted
+ * @errp - [out] The reason (if any) we cannot block migration right now.
+ *
+ * @returns - 0 on success, -EBUSY on failure, with errp set.
*/
-void migrate_add_blocker(Error *reason);
+int migrate_add_blocker(Error *reason, Error **errp);
/**
* @migrate_del_blocker - remove a blocking error from migration
diff --git a/migration/migration.c b/migration/migration.c
index e48dd13..897ae40 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -632,6 +632,26 @@ bool migration_has_failed(MigrationState *s)
s->state == MIGRATION_STATUS_FAILED);
}
+bool migration_has_started(MigrationState *s)
+{
+ if (!s) {
+ s = migrate_get_current();
+ }
+
+ switch (s->state) {
+ case MIGRATION_STATUS_NONE:
+ case MIGRATION_STATUS_CANCELLED:
+ case MIGRATION_STATUS_COMPLETED:
+ case MIGRATION_STATUS_FAILED:
+ return false;
+ case MIGRATION_STATUS_SETUP:
+ case MIGRATION_STATUS_CANCELLING:
+ case MIGRATION_STATUS_ACTIVE:
+ default:
+ return true;
+ }
+}
+
static MigrationState *migrate_init(const MigrationParams *params)
{
MigrationState *s = migrate_get_current();
@@ -667,9 +687,15 @@ static MigrationState *migrate_init(const MigrationParams
*params)
static GSList *migration_blockers;
-void migrate_add_blocker(Error *reason)
+int migrate_add_blocker(Error *reason, Error **errp)
{
+ if (migration_has_started(NULL)) {
+ error_setg(errp, "Cannot block a migration already in-progress");
+ return -EBUSY;
+ }
+
migration_blockers = g_slist_prepend(migration_blockers, reason);
+ return 0;
}
void migrate_del_blocker(Error *reason)
@@ -712,9 +738,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
params.blk = has_blk && blk;
params.shared = has_inc && inc;
- if (s->state == MIGRATION_STATUS_ACTIVE ||
- s->state == MIGRATION_STATUS_SETUP ||
- s->state == MIGRATION_STATUS_CANCELLING) {
+ if (migration_has_started(s)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return;
}
diff --git a/stubs/migr-blocker.c b/stubs/migr-blocker.c
index 300df6e..06812bd 100644
--- a/stubs/migr-blocker.c
+++ b/stubs/migr-blocker.c
@@ -1,8 +1,9 @@
#include "qemu-common.h"
#include "migration/migration.h"
-void migrate_add_blocker(Error *reason)
+int migrate_add_blocker(Error *reason, Error **errp)
{
+ return 0;
}
void migrate_del_blocker(Error *reason)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 7b0ba17..f45baa5 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -731,7 +731,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
error_setg(&invtsc_mig_blocker,
"State blocked by non-migratable CPU device"
" (invtsc flag)");
- migrate_add_blocker(invtsc_mig_blocker);
+ r = migrate_add_blocker(invtsc_mig_blocker, NULL);
+ if (r < 0) {
+ fprintf(stderr, "migrate_add_blocker failed\n");
+ goto fail_mig;
+ }
/* for savevm */
vmstate_x86_cpu.unmigratable = 1;
}
@@ -739,7 +743,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
cpuid_data.cpuid.padding = 0;
r = kvm_vcpu_ioctl(cs, KVM_SET_CPUID2, &cpuid_data);
if (r) {
- return r;
+ goto fail_ioctl;
}
r = kvm_check_extension(cs->kvm_state, KVM_CAP_TSC_CONTROL);
@@ -747,7 +751,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
r = kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz);
if (r < 0) {
fprintf(stderr, "KVM_SET_TSC_KHZ failed\n");
- return r;
+ goto fail_ioctl;
}
}
@@ -760,6 +764,12 @@ int kvm_arch_init_vcpu(CPUState *cs)
}
return 0;
+
+ fail_ioctl:
+ migrate_del_blocker(invtsc_mig_blocker);
+ fail_mig:
+ error_free(invtsc_mig_blocker);
+ return r;
}
void kvm_arch_reset_vcpu(X86CPU *cpu)
--
2.4.3
- [Qemu-block] [PATCH v2] migration: disallow migrate_add_blocker during migration,
John Snow <=